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Download: Besançon S, Foropon MC, This vo Kientza H. 2023. Determination of copper ions in jams produced in copper vessels, 1, 1-17

International Journal of Molecular and Physical Gastronomy(IJMPG)
Research Article

Open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Abstract
Traditionally jams, jellies and marmalades have been made in copper vessels. Chefs and authors
of culinary book sometimes argue that this metal makes “better” products because of its a high
thermal conductivity. However copper consumption should be limited for safety reasons, some chemical forms being toxic. In view of finding best practices for the use of copper vessels, it is usefuf to know how much copper moves from copper vessels towards the jam, jellies and marmalades when they are being made. After the development of an analytical procedure of copper determination applicable to jams, jams were prepared in a copper vessel that
was chosen to be dirty and oxidized (stored in a kitchen without being used for 5 years), in order to
obtain jam samples contaminated with copper ions, and these jams were compared with jams made in the same copper pan after cleaning, and also with jams made in an enamel covered steel vessel; the analysis of a commercial jam advertised to have been made in a copper vessel was performed for comparison. For the interpretation of the measurements of the copper
concentrations, model jams were prepared from water, pectin and sugar, and the
influence of pH was determined through the addition of acids. For all the samples, the
determination of copper concentrations was performed by atomic absorption spectrometry after mineralization (using nitric acid) of jam samples. The dirty and oxidized copper basin did release as much as 48.41 (sd 17.80) mg of copper per kg of jam, whereas only 19.0 (sd 5.94) mg/kg of copper were found in jams prepared in the same vessel, after it had been cleaned using a traditional cleaning process (twice vinegar and salt, plus rinsing with water). However, in the cleaned vessel, the copper concentration rose to 38.3 (sd 6.01) mg/kg when the jam was stored in that same vessel
for 4 hours. For comparison, the copper concentration in jams made in an enameled
covered steel vessel was only 0.52 (sd 0.09) mg/kg. Analysis of the effect of pH showed that the copper concentration increases at low pH (1.3-3.0), but no chelating effect of citric acid was observed.

Keywords
jam, atomic absorption spectrometry, pH, pectins, copper

International Journal of Molecular and Physical Gastronomy. 2023, 1, 1-17 1 Determination of copper ions in jams produced in copper vessels

Stéphane Besançon1, Marie-Charlotte Foropon1, Hervé This vo Kientza1,2 *
1. Université Paris-Saclay, INRAE, AgroParisTech, UMR 0782 SayFood, 22 place de
l’agronomie, 91120, Palaiseau, France.
2. Inrae-AgroParisTech International Centre for Molecular and Physical Gastronomy,
https://icmpg.hub.inrae.fr/ .
*Correspondence: herve.this@inrae.fr

Edited by
Roisin Burke, Technological University Dublin.

Reviewed by
1. Jesus Maria Frias Celayeta, Academic Leader,
Environmental Sustainability and Health Institute,
Technological University Dublin.
2. Linda A Luck, Professor of Chemistry-Emeritus,
State University of New York

Received
15 June 2022

Published
25 January 2023.

Cite as :
Besançon S, Foropon MC, This vo Kientza H. 2023. Copper ions in jams produced in copper vessels, International Journal of Molecular and Physical Gastronomy, 2023, 1, 1-17.